1. Field of the Invention
The instant invention is directed to an elastomeric composition selected from the group consisting of ethylene-propylene-non-conjugated diene terpolymer (EPDM), isobutylene-conjugated diene copolymer (butyl rubber) and mixtures of the terpolymer and copolymer. More particularly, the instant invention is directed to an elastomeric composition selected from the group consisting of ethylene-propylene-non-conjugated diene terpolymer, isobutylene-conjugated diene copolymer and mixtures of the terpolymer and copolymer which may be applied to a roof as roofing sheets or flashing members which, upon exposure to ambient influences, have the ability to crosslink.
2. Background of the Prior Art
Elastomeric ethylene-propylene-non-conjugated diene terpolymer (EPDM) and isobutylene-conjugated diene copolymer (butyl rubber) compositions are well known in the art. The use of EPDM and butyl rubber compositions as the material of construction of roof sheeting is also known in the art. Such sheeting, provided in the cured, or crosslinked, state provide excellent materials for use on a roof in those applications where flat material is acceptable for disposition on equally flat or moderately contoured roofing structures. However, when the crosslinked EPDM or butyl rubber sheeting of the prior art is disposed on intricately contoured surfaces of a roof, such as parapet, chimney, ventilator sections and the like, the flat crosslinked sheeting of the prior art is not acceptable. That is, crosslinked EPDM or butyl rubber lacks the formability to successfully and permanently follow, cover and retain irregular shaped contours.
Roofing material used to follow irregular contours is known as flashing. Crosslinked EPDM or butyl rubber roof sheeting is not normally used as flashing because gaps readily develop around the contours between the sheeting sections of the roof, and those other portions of the roof in which the EPDM or butyl rubber is employed as flashing.
Whereas crosslinked EPDM or butyl rubber sheeting have each established excellent reputations as effective barriers to roof leaks on the surfaces upon which they are applied, still, this protection has not been available to those portions of the roof which are characterized by their irregular shape. Thus, the excellent protection afforded by EPDM or butyl rubber compositions has not been available as flashing. This results in the inability to protect those section of the roof characterized by irregular shape against leakage. The utilization of EPDM or butyl rubber roof sheeting, a most effective long term protector against water leakage, is seriously compromised by this defect in cured EPDM and butyl rubber.